Of Horns and Horner

Of Horns and Horner TZVI POLLOCK Imagine for just a moment, if you will, the vast open plains of Montana. Not the barren, rocky valleys and geologic formations of today, but the broad expanses of primitive grasses and shrubs of the Mesozoic from sixty-seven million years ago. In this lost world, the plains swarm with life. Dragonflies more than six inches long dart back and forth above what is now the Hell Creek rock formation, which, in this past era, still lies largely underwater and teems with fish that have bony plates in place of scales. What would draw your eye the most, though, are the behemoths that roam the plains, dominant and magnificent. A stout, massive quadruped about the size of an elephant waddles along, munching on still prevalent cycads, its entire body covered in armor plates. A monster, twenty feet tall and weighing over seven tons, plods by, its six-inch teeth bared. Its attention is focused on the plains, which thun- der and shake under the weight of a whole herd, elephantine and numerous. They graze the plains, huge frills and horned skulls shaking back and forth. The imagined world of the lost dinosaur. Flash forward to the present. The animals of yesteryear have been extinct for longer than primates have existed. Yet the presence of these majestic crea- tures lives on in the dreams and imaginations of people the world over. From the BBC’s Walking with Dinosaurs special to Jurassic Park, dinosaurs perenial- ly fascinate and entertain. But recently, controversy over two species of dinosaurs evoked a vitriolic and chaotic reaction from the dinosaur-loving community. The Hell Creek fossil formation in Montana is currently one of the richest and most diverse beds of dinosaur fossils in North America, yield- ing such notable original specimens as Ankylosaurus, Tyrannosaurus rex, and Triceratops, among dozens of other species. But recently some paleontologists have posited that two, or perhaps more, of those many species are, in fact, one (Scannella and Horner 1157). These animals are the mighty Ceratopsians, or “horn-faced” dinosaurs, known as Triceratops and Torosaurus. While their exis- MERCER STREET - 73 tence has been central to dinosaur phylogeny, one of the two may be headed the way of Pluto, into the ether of the non-nomen. And, as with Pluto, the real conflict lies not in what scientists rule, but in how that ruling may endanger the public’s preconceptions. In the late 1880s, about a decade before the discovery of Tyrannosaurus rex, the world-renowned paleontologist and bone-hunter Othniel C. Marsh was sent the remains of a new dinosaur. Estimated to weigh more than seven tons, the creature possessed an enormous skull with a beaked jaw, a huge frill shaped from solid bone, and three horns on the face—a small one on the nose and two large ones over the eyes. In 1889, Marsh named the animal Triceratops, “three-horned face,” for its unusual facial accoutrement (173-75). Just two years later, another very similar dinosaur was excavated from the same site. It too possessed a large frill, though its frill was not made of solid bone, and three horns about the face. Marsh named it Torosaurus, “perforated lizard,” to recognize the large holes that distinguish its frill from the solid one of Triceratops (266). Marsh and other paleontologists found over a hundred other species of related Ceratopsian dinosaurs around the world, from the ominously named Diabloceratops to the parrot-like, dog-sized Psittacosaurus. The rest, as they say, is history. We’ve learned about—and learned to love— Triceratops, Tyrannosaurus, and myriad other dinosaurs ever since. That is, until August 2010. The constant danger in the field of paleontology is to mistake one ancient life form for another. The study of prehistoric life, be it dinosaurs, fish, or even plants, relies on clarity of reference, a set of globally accepted classifications. We have endless varieties of life, large and small, whose extinc- tions date from ten thousand years ago to three billion years ago. A common reference system allows us to more accurately and broadly record what par- ticular animals did, where they lived, and to whom they were related. When Darwin solidified his theory of evolution, it was not the living animals of the Galapagos that sparked his hypotheses; it was the ancient remains of the Glyptodont of South America (Quammen). By drawing lines between ancient life forms, we are able to derive the evolutionary history of the organisms we study. It’s vital that we make these distinctions and track their changes so that we can project them forward, extrapolate, and understand the history of our own world. But the danger of misidentifying an organism is ever present. As difficult as it can be to distinguish one species from another in the modern era, doing so when the only remaining evidence is calcified bone can be near- ly impossible. So it stands to reason that, with some frequency, the classifications that scientists have imposed turn out to be inaccurate. 74 - MERCER STREET Notable dinosaur paleontologists John “Jack” Horner and John Scannella had noticed some irregularities when looking at specimens of both Torosaurus and Triceratops. They had access to hundreds of different skulls, and yet none of the Torosaurus skulls were ever identified as belonging to juve- niles. The two animals were found at the same fossil sites with conspicuous frequency, and on Triceratops, Horner and Scannella found depressions in the frill, spaces of decreased thickness that could indicate a transitional stage on the way to full-on temporal fenestrae, or gaps in the frill (Scannella and Horner 1160). Given these factors, the two scientists conferred and crafted a hypothesis: Triceratops, despite its fame and popularity as one of the most rec- ognizable species of dinosaur, was not a true, mature dinosaur genus in its own right, but was instead a juvenile form of Torosaurus (Scannella and Horner 1158). This hypothesis, if endorsed by the scientific community, would elim- inate an age-old species from the evolutionary history of dinosaurs, reducing it to an unfortunate footnote in science textbooks. Horner, whose name is also known outside of paleontology circles, had garnered a reputation before releasing the now infamous “Toroceratops paper.” He was known for routinely striking dinosaur species from the nomenclature by claiming that one species was a juvenile specimen of another. Horner had already pushed for the dinosaur Nanotyrannus to be classified as a growth stage of Tyrannosaurus rex and for both Dracorex and Stygimoloch to be merged with Pachycephalosaurus (Horner and Goodwin 3). In their comparison of Torosaurus and Triceratops, Horner and Scannella compiled Horner’s previous findings, from Ceratopsian ontological data to metaplastic skull composi- tions. The paleontology community responded as groups of experts in a field tend to do when confronted with a controversial new theory: each took a side, some agreeing that the two dinosaurs seemed to be the same species, some accusing Horner of defaulting to the same tactic ad nauseum in a sensationalist play designed to drum up spectacle, and therefore fame, in scientific circles. Longrich and Field refuted Scannella and Horner’s claims and attempt- ed to re-separate the genii. Horner and Scannella collaborated yet again to declare a third species, Nedoceratops, to be another growth stage of Triceratops (Scannella and Horner 2-5). The opposition poked holes in that theory as well (Farke 2). The conflict over Triceratops gives off almost contradictory airs of passive-aggression, with subtle slights against the original paper slipped into the rebuttals, yet hints of a curious camaraderie; Andrew Farke went so far as to discuss how to strengthen his paper with John Scannella at a confer- ence. In fact, while researchers disagreed about the issue, the matter never escalated to the level of controversy in the scientific community; it was those MERCER STREET - 75 following the debate from outside who manufactured scandal. Scientists who accept Horner’s theories disagree with those who do not, yet all share the same goal—and it shows. The constant back and forth of their research, rely- ing as it does on communication and peer-review, makes the theories stronger and more precise—which is what all scientists want, in the end. But the same cannot be said about the reading public. When word got out about Horner and Scannella’s findings, internet followers created an uproar. The conventions of scientific nomenclature dictate that if two genii, previously thought to be distinct, are subsequently combined, the name retained is that of whichever creature was named first. Thus, Triceratops, which was established almost five years before Torosaurus, would retain the species name. But many of the online public were unaware of or ignored this convention, reacting instead to sensational—and inaccurate—headlines like “The Triceratops May Not Be A Real Dinosaur” (Suen), and “Triceratops Never Existed? Say it Ain’t So!” (Rosenthal). Even the suggestion that Triceratops might be stricken from the rolls of dinosaur taxonomy was enough to set off a public outcry against the loss or reclassification of a species that, for many readers, was a beloved childhood icon. This outcry, known colloquially as “#TriceraFAIL” in honor of the trending topic on Twitter, exemplifies the motivations behind the public’s interest (Paul-Choudhury). Rather than examine the facts of the debate or consider the research, much of the viewing public blindly believed the sensationalist reports, speaking out against actual scientific evidence to support what they had been taught was the truth. The average reader wants things to stay the same, wants everything he or she thinks is true to remain true, wants everything that is impossible to remain impossible.

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